Physiologically based pharmacokinetic (PBPK) model for residues of lipophilic pesticides in poultry.

Physiologically based pharmacokinetic (PBPK) modelling has been used to examine the relative importance of physiological differences between laying hens and broiler chickens as well as between broiler chickens and ducks, geese, and turkeys in determining tissue residues. Following exposure in feed, there may be significant differences in tissue residues between laying hens and broiler chickens. The blood lipid content of laying versus broilers, the duration of exposure, and the fraction of the dose absorbed into the systemic circulation were important parameters together with tissue-to-blood partition coefficients. The potential for modelling to improve the extrapolation of residue transfer studies carried out using laying hens to broiler chickens and other poultry is demonstrated.

A new tool for the evaluation of crop residue trial data (day-zero-plus decline).

An approach is presented for the prediction of pesticide residue concentrations in food and feed commodities produced from foliar-treated crops. It uses limited residue trial data and relies on information on spray retention and decline rates of residues following application. The use of the simple approach is demonstrated for residues of a variety of pesticides and the results compared with data sets evaluated by the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) using expert judgement and also with estimates of high residues obtained using statistical methods. It is proposed that the approach should constitute an additional tool for the risk assessment of pesticide residues; it contributes to the estimation of maximum residue limits (MRLs) and high and median residues, which are needed for risk assessment. The approach should be particularly useful in situations where only a few residue trials are available such as often occurs for minor crops.

Influence of physiological status on residues of lipophilic xenobiotics in livestock.

Data on the transfer of lipophilic xenobiotics from livestock feed and the environment to meat and milk are required for risk assessment purposes. Often, data are only available for lactating dairy cattle. Physiologically-based pharmacokinetic (PBPK) modeling has been used to explore differences between classes of food-producing animals. Blood and tissue levels of lipophilic xenobiotics under conditions approximating steady-state were simulated. Simulations of constant exposure were performed for lactating cows, non-lactating cattle, sheep, goats and swine. The tissue : blood partition coefficient, fat volume and fat blood flow were identified as critical determinants of predicted tissue concentrations. There may be significant breed differences in residues in milk and fat following exposure. Modeling was used to derive scaling factors that can be used to assist the extrapolation of transfer studies, carried out on lactating dairy cows, to other classes of cattle and different species.

Monitoring of pesticides and veterinary drugs in Australian cattle: verification of the residue control system.

The Australian National Residue Survey in partnership with the Australian Quarantine and Inspection Service and industry routinely monitors beef to ensure that regulatory requirements for residues are being met. In the 10-year period from 1997 to 2006 a total of 128,902 samples were subjected to residue testing covering veterinary drugs and veterinary and agricultural pesticides in a random monitoring program. Residues of agricultural and veterinary chemicals exceeded the Australian standard in 13 and 7 samples, respectively. Greater than 99% of samples did not contain detectable residues above the Australian standard while greater than 90% of samples did not contain any residues of compounds included in the survey. The results of the surveys provide verification that the Australian residue control system is appropriate and that the requirements of countries importing Australian meat products can be satisfied. The surveys have also demonstrated that industry based programs and state based regulatory controls over sites contaminated with organochlorine residues are effective in managing residues of these chemicals in cattle.

Transfer of fat-soluble pesticides from contaminated feed to poultry tissues and eggs.

1. Implementation of Good Manufacturing Practice and HACCP (Hazard Analysis Critical Control Points) in the production of poultry feed requires efficient tools for profiling risks associated with pesticide use in the production of crops for feed. 2. This paper describes a simple model that may be of use in the first tiers of risk profiling of feeds. 3. The model adequately reproduced the pattern of residues in fat and eggs of laying hens dosed with a selection of lipophilic pesticides that may be used in the production of crops for poultry feeds: deltamethrin, diflubenzuron, fipronil, lindane, piperonyl butoxide and spinosad. 4. Simulations suggest results derived from studies on laying chickens can be extrapolated to other laying birds. 5. Poultry meat production systems focus on maximising growth of birds giving rise to significant potential for dilution of residues that transfer to fat from feed. 6. Simulations of residues in fat of chickens, ducks, geese and turkeys exposed to a lipophilic pesticide with an elimination half-life of one day at 10 mg/kg body weight/d from hatching to typical market ages suggest residues in fat that are highest in turkeys > chickens > geese > ducks. 7. The model is of use in interpreting published dosing studies and predicting likely residues in birds at times after last exposure/dosing.

[Comparison between line immunoassay (LIA) and enzyme-linked immunosorbent assay (ELISA) for the determination of antibodies to extractable nuclear antigenes (ENA) with reference to other laboratory results and clinical features]. / Der Nachweis von Autoantikörpern gegen extrahierbare nukleäre Antigene (ENA) mittels Line Immunoassay (LIA) im Vergleich mit dem Enzyme-linked Immunosorbent Assay (ELISA) in Relation zu anderen Laborparametern und zur Klinik.

INTRODUCTION: The line immunoassay (LIA) for the determination of antibodies to individual extractable antinuclear antigens (ENA) is a development of the enzyme-linked immunosorbent assay (ELISA) in which the antigens to be tested are adsorbed onto a nylon test strip. In addition, the antigen subspecificities B/B' and D in the case of Sm, the 70 kD, A and C components in the case of U1-snRNP and the Ro52 and Ro60 components in the case of SSA/Ro are present separately on the strips. The aim of the study was to determine whether the line immunoassay is suitable for routine laboratory use by means of a comparison with the ELISA. METHODS: Sera from 92 patients stored in our serum bank with known ENA profile as determined by ELISA and with at least one antibody to ENA were tested again with LIA. The clinical features and other available laboratory data taken from the patient records were used to classify the disease according to the relevant diagnostic criteria. In discrepant cases, antibodies to ENA were also determined by Western blot. These data were used to determine which of the two methods gave the more plausible results and to calculate the sensitivity and specificity for each autoantibody. RESULTS: There was good correlation between the two methods, especially for anti-CENP-B (centromere protein B) and anti-Jo1 (histidyl-tRNA transferase) antibodies. For anti-Sm, there was a trend toward higher specificity with the LIA in patients with systemic lupus erythematosus (SLE) if antibodies to Sm D were detected. The LIA was significantly more specific for the detection of antibodies to ribonucleoprotein (RNP) in mixed connective tissue disease and, if antibodies to the 70 kD component were present, also in SLE, although the sensitivity was significantly lower in this case. For anti-SSA/Ro, the specificity of the LIA was significantly higher than ELISA if anti-Ro60 was detected. In the case of anti-SS-B/La, anti-Scl70 (topoisomerase I), anti-CENP-B (centromere protein B) und anti-Jo-1 (histidyl-tRNA transferase), the sensitivity and specificity of the two methods were not significantly different. The LIA was significantly more specific but less sensitive for the detection of anti histone antibodies. CONCLUSION: The suitability of the LIA for routine laboratory determinations was confirmed.

Acute hepatitis in adult Still's disease apparently resulting from oral iron substitution--a case report.

The authors report a case of a young woman with adult-onset Still's disease (AOSD) with massive hyperferritinaemia who developed acute florid hepatitis with intraparenchymatous histiocytic infiltration following oral iron substitution for presumed iron deficiency, which settled on withdrawal of the iron. This suggests that the iron exacerbated the macrophage hyperactivity which is presumed to be present in AOSD. Oral iron substitution in the acute phase of this disease may be inadvisable.

Analysis of the interaction of water with the manganese cluster of photosystem II using isotopically labeled water.

The association of water with the Mn of the water oxidizing complex was investigated using H2(17)O- and 2H2O-reconstituted lyophilized photosystem II particles. The pulsed electron paramagnetic resonance (EPR) technique of electron spin echo envelope modulation (ESEEM) was used to investigate the interaction of the magnetic 2H and 17O nuclei with the paramagnetic S2 state of the Mn complex and other photosystem II components. ESEEM offers a much more specific and sensitive detection of this type of interaction than continuous wave (CW) EPR. Unlike earlier reports using CW EPR, these experiments did not detect any interaction of water with the multiline EPR signal from the S2 state of the Mn complex. No signals indicating specific interaction of either H or O with the multiline signal were detected. Signals due to 2H and 17O were detected only at the Larmour frequency, indicating nonspecific "distant ENDOR" effects. A weak interaction with 17O was detected both in S1, when the Mn is EPR silent, and in S2, but only on the high-field side of g = 2. This interaction may be with the Rieske iron-sulfur center in the cytochrome b6f complex. The results were the same whether the multiline signal was generated by 200 K illumination of dark-frozen samples, or by room temperature illumination in the presence of the inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). Illumination at room temperature in the presence of an electron acceptor to allow multiple turnovers of the system with cycling of the S states did not result in the appearance of any new interactions. These results appear to exclude close (less than 6 A) binding of water to the Mn center giving rise to the multiline signal, and also to exclude mechanisms in which water oxidation involves the breaking and re-formation of the mu-oxo bridges of the Mn complex. They cannot, however, exclude models in which water binding to the manganese complex and direct oxidation by the manganese complex occur in the higher S states, or are catalyzed by one bis(mu-oxo) Mn dimer while oxidizing equivalents are accumulated in the S2 state by a second bis(mu-oxo) Mn dimer.

Addition of dacarbazine or cisplatin to interferon-alpha/interleukin-2 in metastatic melanoma: toxicity and immunological effects.

The combination of chemotherapy and immunotherapy seems to improve response rate in metastatic melanoma. We investigated the effects on toxicity and immunological effects of a single dose of dacarbacin (DTIC; 850 mg/m2) or cisplatin (CDDP; 100 mg/m2) added to subsequent immunotherapy with interferon-alpha (IFN-alpha) and interleukin-2 (IL-2). Twelve patients, who did not respond to IFN-alpha/IL-2 alone were studied. Six received DTIC and IFN-alpha/IL-2, and six received CDDP and IFN-alpha/IL-2. DTIC did not add significant toxicity except for nausea. Significant thrombocytopenia was observed in two patients after CDDP. Although CDDP led to grade 3 nephrotoxicity in two patients, the IL-2-induced fluid retention was less severe than with IFN-alpha/IL-2 alone. Pharmacokinetics of IL-2 were not altered by DTIC, but higher IL-2 serum levels were found in patients with grade 3 nephrotoxicity after CDDP. The IL-2-related induction of secondary mediators (interferon-gamma, tumour necrosis factor-alpha, soluble CD25) was not impaired by chemotherapy and the induction of neopterin was significantly higher after addition of CDDP. One partial response was observed after addition of DTIC to IFN-alpha/IL-2, and one after addition of CDDP. The addition of a single dose of DTIC or CDDP to IFN-alpha/IL-2 is fairly well tolerated and does not abolish induction of secondary mediators. Randomized trials are necessary to test the clinical efficacy.

Investigation of the ammonium chloride and ammonium acetate inhibition of oxygen evolution by Photosystem II.

Using EPR and EXAFS spectroscopies we show that high concentrations of ammonium cations at alkaline pH are required for (1) inhibition of oxygen evolution: (2) an alteration of the EPR properties of the oxygen evolving complex: (3) the ability to detect YZ; and (4) the slow reduction of the Mn complex leading to the appearance of EPR detectable Mn2+. The inhibition of S state cycling, slowing of YZ reduction, appearance of Mn2+ and the yield of a Hpp < 10 mT S3 type EPR signal are decreased by calcium addition. This indicates that these effects were probably associated with calcium depletion arising from the high concentration of ammonium cation. The ammonia-induced changes to the S2 multiline EPR signal are not affected by calcium addition. The appearance of Mn2+ is shown to be reversible on illumination, suggesting that the Mn reduced from the native state is located at or near the native site. Simulations of the interaction which give rise to the S3 EPR signal are also presented and discussed. These indicate that lineshape differences occur through small changes in the exchange component of the interaction between the manganese complex and organic radical, probably through minor structural changes between the variously treated samples.

Path of electron transfer in photosystem 1: direct evidence of forward electron transfer from A1 to Fe-Sx.

Pulsed EPR spectroscopy and selective removal of the iron-sulfur centers in photosystem 1 have been used to study forward electron transfer from the secondary electron acceptor A1. At cryogenic temperatures where forward electron transfer is inhibited, we have observed a g = 2.003 electron spin-echo signal presenting a characteristic phase shift. This out-of-phase signal is attributed to the electron spin-polarized pair P700+/A1-, it decays with t1/e = 23 microseconds, reflecting the recombination reaction. At room temperature the out-of-phase signal is also observed, but it decays with t1/c = 200 ns in untreated photosystem 1, due to forward electron transfer from A1- to one of the iron-sulfur centers. This rate is unchanged in Fe-SA/B-depleted PS1 but is lost when the iron-sulfur center Fe-Sx is removed. In the preparations depleted of all iron-sulfur centers the out-of-phase signal decays with t1/c = 1.3 microseconds, reflecting either the back reaction or the decay of polarization. These results demonstrate that the electron transfer pathway in photosystem 1 is P700-->A1-->Fe-SX-->Fe-SA/B.

Regional adoptive immunotherapy with interleukin-2 and lymphokine-activated killer (LAK) cells for liver metastases.

A phase lb trial of a novel regional approach to adoptive immunotherapy is reported. Patients with liver metastases received continuous high-dose infusion of interleukin-2 (IL-2) into the splenic artery or intravenous infusion with subsequent transfer of lymphokine-activated killer (LAK) cells into the portal vein or the hepatic artery. Trafficking studies revealed homogeneous distribution of the LAK cells within the liver. The usual side-effects of IL-2 and LAK cells occurred without limiting liver toxicity. One partial (7+ months) and two complete responses (36 and 26+ months) were observed in 9 patients with metastases from cutaneous melanoma. None of 6 patients with metastases from ocular melanoma responded.

Analysis of the c-FOS gene on chromosome 14 and the promoter of the amyloid precursor protein gene in familial Alzheimer's disease.

The c-FOS gene product, a putative transacting transcriptional regulator of the amyloid precursor protein (APP) gene, is a candidate locus for the familial Alzheimer's disease (FAD) mutation on chromosome 14 (FAD14). In light of this functional relationship, we investigated the nucleotide sequence and segregation of c-FOS and the nucleotide sequence of the 5' APP promoter. Single-stranded conformational polymorphisms (SSCPs) in the c-FOS gene revealed that c-FOS closely cosegregates with the FAD14 gene but does not show allelic association with FAD. A conservative third-position T-->C mutation was demonstrated in exon 2 (codon 84) of c-FOS, and a C-->G substitution was detected at -209 bp in the 5' promoter of APP. Neither were unique to FAD and are unlikely to be pathogenic or secondary modifiers of the FAD phenotype. We conclude that the c-FOS open reading frame is probably not the site of the FAD14 locus, but we cannot exclude the existence of modifier loci on chromosome 21.

Investigation of the S3 electron paramagnetic resonance signal from the oxygen-evolving complex of photosystem 2: effect of inhibition of oxygen evolution by acetate.

An S3 electron paramagnetic resonance (EPR) signal is observed in a variety of photosystem 2 (PS2) samples in which the oxygen-evolving complex (OEC) has been inhibited. These signals have been proposed to be due to an interaction, S2X+, between the manganese cluster in an oxidation state equivalent to S2 and an organic radical, either oxidized histidine [Boussac et al. (1990) Nature 347, 303-306] or the tyrosine radical Yz+ [Hallahan et al. (1992) Biochemistry 31, 4562-4573]. We report that treatment of PS2 with acetate at pH 5.5 leads to a slowing of the reduction of Yz+ and allows the trapping of an S3-type state on freezing to 77 K following illumination at 277 K. The S3 EPR signal in acetate-treated PS2 has a broader and more complex line shape but otherwise has similar properties to other S3 signals. The addition to acetate-treated samples in the S1 state of the herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), which allows only a single turnover of the reaction center, causes a large reduction in the yield of the S3 signal. Various anion and cation treatments change the S3 signal line shape and are used to show that acetate probably acts by binding and displacing chloride. We propose that a variety of treatments which affect calcium and chloride cofactor binding cause a modification of the S2 state of the manganese cluster, slow the reduction of Yz+, and allow an S3 EPR signal to be observed following illumination.(ABSTRACT TRUNCATED AT 250 WORDS)